I was extremely lucky and picked up a J D Darlington backsaw from an estate sale. The saw is sweet and cuts true, but needs to be sharpened. I've managed to remove the medallion and from the patent date on the medallion (Dec. ?, 186[0/6/9] - I can only say that the final year numeral has to be one of those three) the saw is an 1860s, or 1870s manufacture. The other two nuts however are a different story. I have a decent drive that fits the split nuts nicely but the nuts will not release from the bolt element and turn in the hole. Since the medallion had verdigris developing, it is possible that the other two are worse. Has anyone dealt with this successfully without destroying the nuts?